U.S. patent number 5,819,508 [Application Number 08/627,620] was granted by the patent office on 1998-10-13 for device for removing or twisting off caps from vessels.
This patent grant is currently assigned to Boehringer Mannheim GmbH. Invention is credited to Peter Kraft, Horst Menzler, Hans Schels, Peter Wenzig.
United States Patent |
5,819,508 |
Kraft , et al. |
October 13, 1998 |
Device for removing or twisting off caps from vessels
Abstract
Device for pulling out or twisting off caps from vessels,
wherein the vessel is held, and the cap is removed by means of a
cap-holding device; the cap-holding device executes both a linear
movement in direction of the vessel axis as well as a rotating
movement around the vessel axis. The cap-holding device
advantageously has several clamping jaws that are pressed against
the circumference of the cap.
Inventors: |
Kraft; Peter (Weilheim,
DE), Menzler; Horst (Bernried, DE), Schels;
Hans (Munchen, DE), Wenzig; Peter (Munchen,
DE) |
Assignee: |
Boehringer Mannheim GmbH
(Mannheim, DE)
|
Family
ID: |
7758947 |
Appl.
No.: |
08/627,620 |
Filed: |
April 4, 1996 |
Foreign Application Priority Data
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Apr 6, 1995 [DE] |
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195 12 905.9 |
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Current U.S.
Class: |
53/492;
53/381.4 |
Current CPC
Class: |
B67B
7/182 (20130101); B67B 7/02 (20130101) |
Current International
Class: |
B67B
7/18 (20060101); B67B 7/02 (20060101); B67B
7/00 (20060101); B67B 007/18 (); B67B 007/14 () |
Field of
Search: |
;53/492,381.4,300,331.5,349,353 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 497 112A1 |
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Aug 1992 |
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EP |
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0 639 530A1 |
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Feb 1995 |
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EP |
|
2053747 |
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Apr 1971 |
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FR |
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28 56 432A1 |
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Jul 1980 |
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DE |
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U-94 03 243.2 |
|
Sep 1994 |
|
DE |
|
58-34352 |
|
Jul 1983 |
|
JP |
|
2-27235 |
|
Jun 1990 |
|
JP |
|
6-8995 |
|
Jan 1994 |
|
JP |
|
1245081 |
|
Sep 1971 |
|
GB |
|
2 010 789 |
|
Jul 1979 |
|
GB |
|
Primary Examiner: Culver; Horace M.
Attorney, Agent or Firm: Nikaido, Marmelstein Murray &
Oram LLP
Claims
We claim:
1. A device for removing caps from vessels, said device
comprising:
first vessel holding means for holding a first vessel therein;
a cap holding means adjacent said first vessel holding means, said
cap holding means including holding elements for holding a cap of
the first vessel;
moving means coupled to said cap holding means for moving the cap
holding means in a direction which is parallel to an axis of the
first vessel, and for rotating the cap holding means around the
axis of the first vessel wherein said moving means comprises a
threaded rod attached to said cap holding means, said threaded rod
being engaged in a rotatable nut; said device further
comprising
holding means for selectively holding the rotatable nut, thereby
selectively preventing the rotatable nut from rotating, thereby
enabling selective conversion of a rotation of the threaded rod
into linear movement of the cap holding means.
2. A device as recited in claim 1, wherein an outer circumference
of the rotatable nut includes indentations thereupon, and wherein
said holding means comprises a tappet which is selectively
activated to engage the indentations.
3. A device as recited in claim 1, further comprising cap
receptacle means for receiving removed caps therein, said cap
receptacle means including a movable lever with a cap receiver
attached thereto, said movable lever being movable from a first
position below the cap holding means whereby caps held by the cap
holding means are received in the cap receiver, and a second
position away from the cap holding means.
4. A device as recited in claim 3, wherein said cap receiver
comprises an elastic tube.
5. A device as recited in claim 1, wherein the holding elements of
the cap holding means comprise at least two clamping jaws having a
space therebetween, each of said at least two clamping jaws being
movable from a first position to a second position by a drive
means, wherein the space between the at least two clamping jaws
when the clamping jaws are in the first position is larger than a
diameter of the cap whereby the cap can be disposed in the space,
and wherein, when the at least two clamping jaws are moved to the
second position, the at least two clamping jaws engage an outer
circumference of the cap.
6. A device as recited in claim 5, wherein the drive means for
moving the at least two clamping jaws comprises a first plate and a
second plate, said first and second plates being disposed around a
common axis, said drive means comprising a rotating means to rotate
the first plate relative to the second plate, and wherein each of
said at least two clamping jaws is rotatably connected to the first
plate, and wherein each of the clamping jaws is coupled to the
second plate by pins.
7. A device as recited in claim 5, wherein the cap holding means
comprises at least four clamping jaws.
8. A device as recited in claim 6, wherein the cap holding means
comprises at least four clamping jaws.
9. A device as recited in claim 5, wherein said cap holding means
includes a maximum of eight clamping jaws.
10. A device as recited in claim 6, wherein said cap holding means
includes a maximum of eight clamping jaws.
11. A device as recited in claim 5, wherein an edge of each of the
clamping jaws includes a toothed portion thereupon, said toothed
portion for engaging the cap.
12. A device as recited in claim 11, wherein each toothed portion
comprises a plurality of individual teeth, with the individual
teeth decreasing in size from a first side of the edge to a second
side of the edge.
13. A device as recited in claim 5, wherein each of said at least
two clamping jaws include spikes which engage the cap.
14. A device as recited in claim 5, wherein each of said at least
two clamping jaws include needles which engage the cap.
15. A device as recited in claim 1, wherein said moving means is
configured to linearly move the cap holding means along the axis of
the first vessel, and to simultaneously rotate the cap holding
means around the axis of the first vessel.
16. A device as recited in claim 1, wherein said moving means
comprises a threaded rod rotatably driven by a motor, said threaded
rod engaging a stationary thread wherein rotational movement of the
threaded rod by the motor is converted into linear motion, thereby
linearly and rotatingly moving the cap holding means.
17. A device as recited in claim 1, wherein the first vessel
holding means comprises at least two vessel holding jaws configured
to engage the first vessel in a space therebetween, said at least
two vessel holding jaws being movable with respect to each other to
increase and decrease the space therebetween.
18. A device as recited in claim 17, wherein the vessel holding
jaws are tiltable with respect to the axis of the vessel.
19. A device as recited in claim 1, further comprising a conveyor
belt disposed adjacent said vessel holding means, for transporting
a plurality of vessels including the first and second vessels to a
position beneath the first vessel holder in a successive
manner.
20. A device as recited in claim 1, wherein said first vessel held
in said first vessel holding means is a sample vessel.
21. A device for removing caps from vessels, said device
comprising:
first vessel holding means for holding a first vessel therein;
a cap holding means adjacent said first vessel holding means, said
cap holding means including holding elements for holding a cap of
the first vessel;
moving means coupled to said cap holding means for moving the cap
holding means in a direction which is parallel to an axis of the
first vessel, and for rotating the cap holding means around the
axis of the first vessel, wherein the holding elements of the cap
holding means comprise at least two clamping jaws having a space
therebetween, each of said at least two clamping jaws being movable
from a first position to a second position by a drive means,
wherein the space between the at least two clamping jaws when the
clamping jaws are in the first position is larger than a diameter
of the cap whereby the cap can be disposed in the space, and
wherein, when the at least two clamping jaws are moved to the
second position, the at least two clamping jaws engage an outer
circumference of the cap, wherein an edge of each of the clamping
jaws includes a toothed portion thereupon, said toothed portion for
engaging the cap, and wherein each toothed portion comprises a
plurality of individual teeth, with the individual teeth decreasing
in size from a first side of the edge to a second side of the
edge.
22. A device for removing caps from vessels, said device
comprising:
first vessel holding means for holding a first vessel therein;
a cap holding means adjacent said first vessel holding means, said
cap holding means including holding elements for holding a cap of
the first vessel;
moving means coupled to said cap holding means for moving the cap
holding means in a direction which is parallel to an axis of the
first vessel, and for rotating the cap holding means around the
axis of the first vessel; and
a second vessel holding means configured to move at least the first
vessel and a second vessel with respect to said cap holding means,
such that when the first vessel holding means is disposed below the
cap holding means, the second vessel holding means is disposed to
receive the second vessel therebetween, and wherein the first and
second vessel holding means can be moved through movement of a
common rotating arm, thereby moving the first and second vessels
relative to said cap holding means.
23. A device for removing caps from vessels, said device
comprising:
first vessel holding means for holding a first vessel therein;
a cap holding means adjacent said first vessel holding means, said
cap holding means including holding elements for holding a cap of
the first vessel;
moving means coupled to said cap holding means for moving the cap
holding means in a direction which is parallel to an axis of the
first vessel, and for rotating the cap holding means around the
axis of the first vessel; and
a grabbing means for grabbing and moving the first vessel from a
rack to the first vessel holding means.
24. A method for removing caps from vessels, said method comprising
the steps of:
holding a vessel in a vessel holder;
holding a cap of the vessel in a cap holding device;
linearly and rotatingly moving the cap holding device through
actuation of a moving means, thereby removing the cap from the
vessel, wherein said step of pulling the vessel from a rack
comprises steps of engaging the vessel with a grabbing means at a
first pressure;
relieving the first pressure and moving the grabbing means in a
direction whereby the grabbing means engages the vessel and an
upper portion thereof, under an upper edge thereof.
25. A method as recited in claim 24, comprising a first step of
pulling a vessel from a rack with a holding means, then introducing
the cap into the cap holding means.
26. A method as recited in claim 24, wherein said step of holding a
vessel in a vessel holder comprises holding a sample vessel in the
vessel holder.
27. A method as recited in claim 24, comprising a first step of
moving a rack of vessels underneath the vessel holding means with a
conveyor belt, wherein the vessels in the rack are successively
disposed under the vessel holding means.
Description
The present invention addresses a device for pulling out or
twisting off caps from vessels, particularly sample vessels
comprising
a vessel holder in which the vessel is held such that the cap of
the vessel is freely accessible,
a cap-holding device with holding elements to hold the cap,
a device for moving the cap-holding device essentially parallel to
the axis of the vessel and rotate the cap-holding device around
said vessel axis.
Devices for removing caps from vessels are used in particular in
the field of clinical analysis where numerous sample vessels are
used, which are closed with stoppers or caps which must be removed
prior to analysis.
Prior art already knows automated devices to remove stoppers from
sample vessels. U.S. Pat. No. 5,340,544, for example, describes an
apparatus to remove rubber stoppers from sample vessels. This is
accomplished in that leave springs laterally approach the rubber
stoppers to push them out of the vessel. European patent
applications EP-A-0 487 492 and EP-A-0 487 493 describe devices
that are based on a similar principle. In the devices described in
these applications, a needle is laterally introduced into the
rubber stopper and moved along a guiding element such that the
stopper is pushed out of the vessel. European patent EP-B-0 264 456
also describes an apparatus for pulling stoppers out of sample
vessels. This apparatus features a holding device for the sample
vessels, and a mechanism where the two stoppers are embraced by two
opposite clamping jaws. Said clamping jaws are then contracted
while spikes are pushed into the rubbers in order to improve the
holding procedure. The stopper is removed in that the device
together with the clamping jaws is being moved away from the sample
vessel.
It is a draw-back of the devices known in prior art that only
stoppers can be removed, however, not screw caps. This restriction
to stoppers means that not all types of the sample vessels used in
the practice can be processed in such a manner.
It was, hence, an object of the invention to propose a device which
allows removing stoppers as well as screw caps. It was also an
object of the invention to propose a device which can be used to
remove caps from any desired sample vessel used in the
practice.
It was found that this object can be accomplished by a device for
pullig out or twisting off caps from vessels which has
at least one vessel holder to hold a vessel such that the cap of
the vessel is freely accessible,
a cap-holding device with holding elements to hold the cap, and
a device for moving the cap-holding device essentially parallel to
the axis of the vessel and to rotate the cap-holding device around
said axis.
In the vessel holder, a sample vessel is held such that the removal
of a cap is possible. A prerequisite therefore is that the vessel
holder acts as a counterpart to the forces that are exerted when
pulling out or twisting off caps. The vessel-holding device must,
hence, be configured such that it reduces to a largest possible
extent both rotating movements and linear movements of the vessels.
The sample vessels that are commonly used are reagent tubes made of
glass or plastic. The vessel holder must, hence, be configured such
that it acts as a holding device without exerting too great a
pressure onto a sample vessel thus preventing the destruction of
the vessel. A suitable device for holding reagent vessels is
described for example in EP-B-0 264 456. In accordance with the
invention, a vessel holder that is particularly suitable is one
where the reagent vessels are held between clamping jaws made of a
relatively elastic material such as rubber. The clamping jaws in
turn are, via adjusting elements, attached to an axis where it can
be tilted with respect to the axis of the vessel. It has proven to
be particularly simple when the adjusting elements can be moved
away from or towards each other via a spindle drive in order to
thus open or close the vessel holder. Such a spindle drive can be
advantageously driven via one single motor to move one pair of
adjusting elements, provided that the spindle drive for both
adjusting elements is located on a single threaded rod where one
segment has a right-handed thread and the other segment a
left-handed thread.
The described vessel holders can be operated together with racks
for sample vessels. On racks that are commonly used in the
practice, several reagent vessels are provided in a linear
successive arrangement. Such a rack can be operated together with a
vessel holder in that the rack is pushed between the clamping jaws
of the vessel holder. If the rack is configured such that the
sample vessels are accessible from the side, sample vessels can be
held by the clamping jaws without pulling out the sample vessel to
remove the cap.
In a particularly preferred embodiment, the sample rack is placed
on a conveyor belt where the individual vessels are successively
passed underneath a cap-holding device. A vessel located underneath
the cap-holding device is lifted by a grab, and the cap of the
device is inserted into the cap-holding device. Experience has
shown that it is expedient to have a grab with a relatively simple
mechanical structure, and to provide a separate device to hold the
vessel during the twisting. If an additional grab is provided, this
vessel-holding device can be stationary.
It is also possible to employ the rotors for sample vessels used in
some instruments, where the sample vessels are arranged in a circle
together with the above described vessel holders. A prerequisite is
that the vessels can be accessed from the side. It is, of course,
also possible to use a robot arm to remove the sample vessels from
any desired rack and place them into the vessel holder.
The invention advantageously proposes a vessel holder which
consists of two vessel holders that are commonly attached to one
rotating arm. One of these two vessel holders is always in a
position that is accessible for the cap-holding device, usually
underneath that cap-holding device. The second vessel holder is
then in a position where closed sample vessels can be loaded. Once
the vessel located in the first position, has been opened, another
closed vessel is in the second position; now the rotating arm
performs a rotation, where the two positions are exchanged. The
still closed vessel can be opened and the already opened vessel is
transported away for further processing. The here described device
is particularly suitable for incorporation in a conveying system
where the sample vessels individually pass numerous stations where,
for example, labels are attached, and pipetting, diluting or
centrifugation steps are carried out.
If the intention is to reduce the time requirement necessary to
remove the caps from the vessels, it is expedient to select an
arrangement wherethe vessels are placed in racks and the racks are
passed underneath the cap receiver. The vessels to be opened can be
only merely lifted; it is not necessary to completely remove the
vessels from the rack.
A cap-holding device is equipped with elements to hold the caps. It
is possible, for example, to use a cap-holding device as the one
described in FIGS. 11 to 15 of European patent EP-B-0 264 456 or a
similar device. The invention, however, comprises a novel
cap-holding device that has proven to be particularly advantageous
for this special application. The cap-holding device in accordance
with the invention features a multitude of gripping jaws,
preferably 4 to 8 and more preferably 6. The gripping jaws are
arranged around a center and essentially on one plane. A drive unit
allows to move the gripping jaws from a first position into a
second position; in the first position there is a space left
between the gripping jaws that is sufficiently large to receive the
respective cap that has to be removed. In order to handle a cap
diameter of 11 to 19 mm that is commonly used in clinical practice,
a distance of greater than 19 mm between the gripping jaws has
proven to be suitable. In the second position, the gripping jaws
have approached one another such that the removed cap is held
between the jaws. From the object of the invention, to handle
different types of caps, it can be concluded that the second
position is not a fixed position but a variable on which can be
adjusted to match the respective cap. For reasons of simplicity,
the first position is preferably selected such that all caps
commonly known in the practice fit between the two gripping jaws.
The drive unit used to move the gripping jaws can be a pressurized
cylinder or a spindle drive. In accordance with the invention,
however, a drive unit was found which simultaneously moves all
gripping jaws in a simple manner. This drive unit comprises two
plates in a parallel arrangement which are rotated in counter sense
perpendicular to their planes with the aid of a plate drive. The
two plates preferably have circular recesses in the area of their
axes of rotation. A connecting axis is used to rotatably connect
each of the gripping jaws with the first plate; each such element
can then be rotated around its connecting axis with the first plate
with the aid of pins that are attached to the second plate. The
pins of the second plate preferable engage recesses in the gripping
jaws which serve as guiding rails. The guiding rails and the
connecting axis are arranged such that the tips of the clamping
jaws move away from the center to receive the cap when the plates
are rotated in counter sense such that the connecting axis on the
first plate and the pins of the second plate move away from one
another. Owing to this counter sense rotation, the gripping jaws
can move toward a common center to hold a cap that is now located
between the two jaws. It was found to be advantageous if the edges
and/or surfaces of the gripping jaws which press against the cap,
are configured as toothed edges or surfaces. It has proven to be
particularly advantageous if the gripping jaws are provided with
needles or spikes which at least partially penetrate the cap when
the latter is held.
The cap holding device is preferably located on a device for moving
the cap-holding device essentially parallel to the axis of the
vessel and to perform a rotation of said device around the axis of
the vessel. This moving device can be a robot arm, for example, to
execute the corresponding movements with the cap-holding device.
Moreover, it is conceivable that the moving device is configured as
a rigid toothed bar along which the cap-holding device is moved up
and down with the aid of a gear wheel drive while a separate motor
is used to rotate the cap-holding device. The invention has found a
particularly simple solution for this moving device wherein one
single motor drives a screw located at the cap-holding device. This
screw is located in a nut such that, when the motor rotates the
cap-holding device, it executes a rotation around the axis of the
screw and also a linear movement in direction towards the axis of
the screw. For the caps used in the practice, it has proven to be
particularly advantageous if the rotation of the cap-holding device
is one of 400.degree., and if the screw is selected such that the
advance of the cap-holding device during this rotation is 9 mm.
Good results were also obtained with an angle of rotation for the
vessel holder of greater than 300.degree. and with an advance of
the vessel holder of at least 5 mm.
The aforementioned embodiment could further be improved by
rotatably mounting the nut which the screw of the cap-holding
device engages, and by providing a pin which engages in a toothed
segment on the outer edge of the nut and which can be arrested in
position. With this arrangement it is possible to use the
cap-holding device not only for removing caps from vessels but also
to rotate the vessels, e.g. in order to read a barcode.
In order to lower the cap-holding device on the cap, it may be
necessary that the cap holder has to travel relatively large
distances in direction of the axis of the vessel. In this case, the
invention proposes that the nut which the screw of the cap-holding
device engages also moves in direction toward the axis of the
vessel.
The invention also addresses a method for opening vessels,
particularly sample vessels, by pulling out or twisting off caps,
wherein
a vessel is held in a vessel holder,
a cap-holding device holds the cap of the vessel, and
the cap-holding device is moved with the aid of the device such
that it removes the cap from the vessel by executing a linear and
rotating movement.
In the aforementioned method, it is possible to use the already
described apparatus in accordance with the invention. In order to
implement the method, a vessel must be located in a vessel holder
such that the upper end where the cap is located is accessible for
the cap-holding device; i.e. the cap must project out of the vessel
holder, and the circumferential area around the cap must be free of
interfering components. In order to open the cap, the cap-holding
device is first lowered onto the cap or the cap is introduced into
the cap-holding device such that the cap is located in the center
between the two gripping jaws. Since the apparatus of the invention
is designed to process a multitude of different types of sample
vessels and caps, it should also feature a device which controls
the lowering of the cap-holding device or the lifting of the vessel
in such a manner that the cap in question can be retained by the
gripping jaws at any time. A mechanical detection mechanism for the
upper edge of the stoppers has been described, for example, in
European patent application EP-A 0 467 470. European patent
application EP-A-0 467 302, however, describes an optoelectronic
system to scan sample vessels. The latter system can be
advantageously used with this invention since it recognizes not
only the upper edge of the stopper but also the dimensions of the
stopper; the cap-holding device can then be controlled such that
the cap is held in a well-suited position. The disclosures of
patent applications EP-A 0 467 470 and EP-A-0 467 302 are therefore
included in this application.
In accordance with the invention, a particularly simple method was
found to suitably position vessels in order to remove caps. This is
accomplished in that a grab with clamping jaws first holds the
vessel, then the clamping jaws are slightly opened and the grab is
moved upwardly; the gripping jaws now reach a position underneath
the edge of the vessel opening or underneath the cap. The grab now
introduces the cap into the cap-holding device in such a manner
that the holding device is located only a few millimeters above the
clamping jaws of the grab. Experiments have shown that this is a
very simple and efficient method to move the caps of the
cap-holding device into a suitable position without requiring
complex position recognition systems.
If, however, the device of the invention is used to process sample
vessels where a multitude of different operations is carried out,
the scanning of the sample vessel can be carried out at a location
that is remote from the device in accordance with the invention,
since the scanning of the sample vessels is usually one of the
first steps. The data received in the scanning procedures is used
for numerous different operating steps during the processing.
The suitable control of the device for moving the cap-holding
device can advantageously be accomplished with a microprocessor.
Said microprocessor processes data received during the scanning of
the sample vessels and controls the individual movements such as
the lowering, rotating, and lifting of the cap-holding device. When
using such a microprocessor, the types of sample vessels and caps
commonly used in the practice can be advantageously stored; this
allows identification of the sample vessel and the cap with
relatively simple optical and mechanical scanning devices;
characteristic data that has not been determined during the
scanning, such as diameter of the cap and elasticity of the cap,
can be read off a table.
The method of the invention for removing caps can be divided into
the following steps:
The moving device moves the cap-holding device into an initial
position, and the presence of the cap-holding device in this
position is detected via a light barrier.
In the cap-holding device, the first and second plates are rotated
with respect to each other such that the clamping jaw move away
from each other in order to open the cap-holding device to receive
a cap.
A closed vessel is introduced into the vessel holder and held
therein.
The moving device lowers the cap-holding device onto the cap of the
vessel or the cap is introduced into the cap-holding device.
Unless the cap-holding device is already in a suitable position
with respect to the cap, it is now moved into a position where the
clamping jaw are on one level with the cap or the cap in turn is
correspondingly lifted.
The first and second plates in the cap-holding device are rotated
with respect to each other in such manner that the clamping jaw
move towards one another in order to hold the cap.
The moving device rotates the cap-holding device and moves it
upwardly.
The moving device moves the cap-holding device back into its
initial position.
The plates in the cap-holding device are rotated with respect to
one another such that the clamping jaw release the cap.
The invention is now explained in greater detail with reference to
the drawing.
FIG. 1 is a lateral view of the cap holding device and the moving
device.
FIG. 2A is a cross section of the cap holding device in its open
position. FIG. 2B is a cross section of the cap holding device in
its closed position. FIG. 2C is a view of an individual gripping
jaw.
FIG. 3 shows the vessel holder.
FIG. 4 is a perspective representation of a second embodiment.
FIG. 5 is another embodiment of the cap holding device.
FIG. 6A is a top plan view of the vessel holder. FIG. 6B is a side
cross section of the vessel holder.
FIG. 7 shows a gripping arm
FIG. 8A is a side cross section of a receptacle for removed caps.
FIG. 8B is a top plan view of the receptacle for removed caps.
FIG. 1. shows the cap holding device (10) and the moving device
(20) in a lateral view. The housing of the cap holding device forms
the first plate (11) of the cap holding device (10); the second
plate (12) is located in the interior of the housing, and has the
form of a circular ring with an outer toothed ring. A rotation of
the first plate (11) and the second plate (12) is accomplished with
the aid of a drive motor (13) which is mounted on the first plate
(11); the shaft of said motor is provided with a toothed wheel
which engages the teeth of the second plate (12).
A screw (21) which engages a nut (22) is located on the top of the
cap holding device (10). Screw (21) is rigidly connected to the
axis of a second drive motor (23) which rotates the screw. Said
drive motor (23) has a catch (24) to prevent a rotation of the
motor housing, but allows an up and down movement of the motor.
When the drive motor (23) rotates, the arrangement of cap holding
device (10), screw (21), and drive motor (23) moves parallel to the
axis of rotation while the nut (22) remains fixed in its position.
In order to move the entire arrangement of vessel holder (10) and
movement device (20) parallel to the axis of rotation, the
invention proposes to move the nut (22) via a drive, e.g. via a
rack drive, to allow rapid movement of the arrangement to cover
larger distances.
FIG. 2 is a cross section of the cap holding device in accordance
with the invention from its bottom (view X). In this
representation, it can be seen that the gripping jaws (14) are
rotatably connected to the first plate (11) via an axis (15) which
is attached to their ends. The gripping jaws (14) have a recess
(16) to guide pins (17) which in turn are rigidly mounted on the
second plate (12).
FIG. 2A shows the cap holding device in its open position from
which it is closed by clock-wise rotating the second plate
(12).
FIG. 2B shows the cap holder in a position where the gripping jaws
(14) hold a cap (30).
FIG. 2C shows an individual gripping jaw (14) with the recess (16)
and the toothed segment (18) at its arrow-like tip. At the tip of
the gripping jaw, the individual teeth (18) are spaced apart at a
relatively large distance. The distance between the individual
teeth and, hence, the size of the individual teeth decreases with
an increasing distance to the tip. Such a configuration of the
toothed segment has proven to be particularly advantageous when the
vessel holder is used to hold relatively small as well as
relatively large caps.
FIG. 3 shows an arrangement (40) of two vessel holders which are
both mounted on a common axis (45). Each vessel holder has two
clamping jaws (41, 41') which are connected to the adjusting
elements (42, 42') via an axis (46). By mounting the clamping
jaws(41) to an axis (46), the jaws can be tilted thus allowing a
more effective grip of the sample vessels. The adjusting elements
(42, 42') are slideably located on the rotating arm (45) and are
equipped with threads in which a spindle (43, 43') is located. Each
spindle (43, 43') has both a left-hand and a right-hand thread. The
spindles are driven via a motor (44 and 44') in order to move the
clamping jaws (41, 41') towards or away from each other. The entire
arrangement of two vessel holders can be swung via a rotating arm
that is rotatably mounted on an axis (47).
With the device shown in FIG. 3 it is, hence, possible to hold a
closed sample vessel in one of the vessel holders in order to open
said vessel and, at the same or a different time to start
processing a second still closed sample vessel in the second vessel
holder. Once the vessel held in the first vessel holder has been
opened, the rotating arm (45) is rotated around axis (47) such that
the two vessel holders exchange positions. The now opened vessel
can be removed from the vessel holder and at the same or a
different time, the still closed vessel can be opened.
FIG. 4 is a diagrammatic perspective view of another embodiment to
increase the throughput of vessels. Individual components of the
second embodiment are shown separately in FIGS. 5-8.
The device of FIG. 4 has a left and a right leg (55, 51). Between
these legs, a conveyer belt (52) passes to convey racks with sample
vessels. The belt is arranged such that the vessels in the rack are
successively passed underneath the vessel holder. The conveyer belt
(52) can be controlled such that it stops when a sample vessel is
located underneath the cap holding device.
A grab (53) to remove vessels from a rack or to lift a vessel in
the rack is located at the left leg (50). The grab (53) is, for
example, located on a spindle to be moved up and down.
In order to feed a cap to the cap holding device, grab (53) moves
upwardly such that it comes to a rest above the clamping jaws (54)
of the vessel holder. In this position, elements (54) hold the
vessel. The height to which grab (53) lifts the vessel is selected
such that the cap holding device (10) is able to hold the cap. An
advantage of this embodiment is that the relatively heavy cap
holding device must not be moved over larger distances toward a
cap. By avoiding the acceleration of larger masses, it was possible
to reduce the time required to execute the cycles in the system in
question.
FIG. 4 is a diagrammatic representation of another cap holding
device (10) with a rotatably mounted nut (55); on its
circumference, said nut is provided with indentations. These
indentations are engaged by a tappet (56) to prevent a rotation of
nut (55). In this embodiment, the cap holding device (10) is, via a
toothed belt (57), driven by a motor (58)
FIG. 4 also shows a receptacle for caps that were twisted off; said
receptacle has a lever (60) with an elastic tube (61).
FIG. 5 shows a variant of the cap holding and moving devices shown
in FIG. 1. The region of the cap holding device (10) has not
undergone essential modifications; the description of FIG. 1,
hence, still applies. With respect to the cap holding device (10),
however, it can be seen that the clamping jaws are provided with
spikes (70) which enter at least partially the cap material when
holding such caps.
In this and in the first embodiment, said cap holding device (10)
is located on a threaded rod and/or screw (21). As opposed to the
first embodiment, the nut (55) is rotatably located in ball
bearings (71). In its upper part, the circumference of the nut (55)
is provided with indentations, e.g. corresponding to the two
segments of a toothed wheel, such that tappet (56) engages these
indentations. Tappet (56) is moved via a lifting magnet (72). In
its resting position, the tappet (56) is largely inside the lifting
magnet (72) and it does not engage the indentations of nut (55).
When magnet (72) is activated, tappet (56) engages the indentation
of nut (55).
Threaded rod (21) to which the holding device (10) is mounted, is
driven via a motor (73) with the aid of a toothed belt (57). Said
toothed belt (57) runs via a first toothed wheel (74) located on
the axis of the motor (73), and via a second toothed wheel (75)
which is rigidly connected to the first threaded rod (21).
Provided nut (55) is not arrested in its position and a threaded
rod (21) is driven via motor (73), the cap receiver (10) is rotated
without executing a linear movement. This can be advantageously
used when the entire sample vessel is to be rotated prior to
removing the cap, e.g. to read off a bar-code on the vessel or to
determine the filling level. If, however, nut (55) prevents a
movement of tappet (56), the rotation of the a threaded rod (21) is
partially converted into a linear movement, and the cap holding
device (10) executes both a linear and rotating movement. The
advantages of removing caps by executing this type of movement have
already been described in greater detail in connection with the
first embodiment.
FIG. 6 shows an improved embodiment of the vessel holder. It has
been found that it is imperative for the proper functioning of the
vessel holder that the position of the vessel axis be exactly
defined for each operating cycle and to avoid any displacement
between individual cycles. It is, hence, advantageous to use a
single motor (80) to drive the vessel holder which transfers its
rotating movement on both vessel clamping jaws (54). A damping
element (81) which serves to avoid heavy mechanical stress on the
vessels when the vessel holder is closed is provided on the axis of
motor (80). This damping element (81) is made of a flexible
material, usually plastic, which is located between two metal
disks; said disks are rigidly connected with the respective part of
the axis. If the vessel is already tightly held by the clamping
jaws, while the movement of the motor is continued due to motor's
inert behavior or a delay of the detection, the elastic material of
the damping element is compressed and a destruction of the vessel
is thus prevented. The damping element (81) is followed by a drive
axis (82) to which two toothed wheels are mounted, said toothed
wheels in turn drive a toothed belt. In the area of the vessel
clamping jaws (54), these toothed wheels drive toothed belts which
are connected to a cone (83) whose outer circumference is provided
with a pin. The vessel clamping jaws (54) are each equipped with a
cylinder to surround the cones (83); at its inner side, the
cylinder has a groove into which the pin of the cone can engage.
The vessel clamping jaws (54) are mounted such that they can only
execute a linear movement, but not a rotating movement. When the
cone (83) is rotated, the interaction of pin and groove allows a
movement of the vessel clamping jaws (54) towards or away from each
other depending on the sense of rotation of the cone.
FIG. 7 shows a grab (53) of a relatively simple design. Each of the
two gripping jaws (90) has a thread which runs on a threaded rod
(91); said a threaded rod is provided with two threads of opposite
orientation. For a detailed description, refer to FIG. 3. The a
threaded rod (91) is connected with the axis of a motor (92). By
rotating the axis of the motor, the gripping jaws (90) are moved
towards or away from each other depending on the sense of rotation.
In order to avoid a destruction of the vessels, it is possible to
provide a damping element (81) between the axis of the motor and a
threaded rod (91).
The function of the grab is to take a vessel and feed it to the cap
holding device in a suitable manner. Experience has shown it to be
advantageous if the grab (53) first tightly embraces a vessel with
the aid of its gripping jaws (90) and then slightly releases its
grip by a counter-directed movement of the motor. The vessel can
now be shifted along the axis of the vessel between the gripping
jaws (90) while a lateral displacement is avoided. If the grab (53)
is moved upwardly, the vessel slides through the gripping jaws (90)
along its longitudinal axis until the edge of the vessel or the cap
comes to a rest on the gripping jaws (90). Based on the position of
the gripping jaws which is known to the device, it is now possible
to determine the position of the cap with sufficient accuracy. A
separate detection of the cap is, hence, no longer required.
FIG. 8 shows another improvement of the device of the invention to
dispose of removed caps in a simple and contamination-free manner.
At its one side, lever (60) is rigidly connected to the axis of a
motor (93) and can be swung out with the aid of said motor. On its
other side, the lever is provided with a annular opening into which
a tube (61) ends. A flag (95) which can be detected by light
barriers (94) is also connected to the lever.
The receptacle functions in such a manner that when a cap is
twisted off from the vessel, the annular opening of the lever is
moved underneath the cup holding device (10); the cap holding
device then releases the cap such that said cap falls through the
annular opening of the lever into tube (61). After this procedure,
lever (60) is moved out of the area of the cap holding device so as
to not interfere with successive operating steps. The lever must,
hence, assume at least two positions; the first position is one
underneath the cap holding device while the second one is outside
this area. Light barriers are used for proper recognition of these
positions.
Tube (61) of the receptacle can be made of a plastic or a woven
material. The tube should be dimensioned such that the caps sliding
through it arrive in a receiving zone where they do not interfere
with the proper functioning of the device and do not cause
contamination.
List of reference numerals
(10) Cap holding device
(11) First plate
(12) Second plate
(13) Drive motor
(14) Gripping jaws
(15) Axis
(16) Recess
(17) Pin
(18) Toothed area
(20) Moving device
(21) Screw
(22) Nut
(23) Drive motor
(24) Catch
(30) Cap
(40) Arrangement with two vessel holders
(41, 41') Clamping jaws
(42, 42') Adjusting elements
(43, 43') Spindle
(44, 44') Drive motor
(45) Rotating arm
(46) Axis of the clamping jaws (41, 41')
(47) Axis of the rotating arm (45)
(50) Left leg
(51) Right leg
(52) Conveyer belt
(53) Grab
(54) Vessel holding elements
(55) Nut
(56) Tappet
(57) Toothed belt
(58) Motor
(60) Lever
(61) Tube
(70) Pin
(71) Ball bearing
(72) Lifting magnet
(73) Motor
(74) First toothed wheel
(75) Second toothed wheel
(80) Motor
(81) Damping element
(82) Drive axis for toothed wheels
(90) Gripping jaws
(91) Threaded rod
(92) Motor
(93) Motor
(94) Light barrier
(95) Flag
* * * * *